//
//  CZMainTabBar.swift
//  新浪微博
//
//  Created by gv pro on 16/3/20.
//  Copyright © 2016年 gv pro. All rights reserved.
//

import UIKit

let TabBarItemCount = 5
class CZMainTabBar: UITabBar {
    
    override func layoutSubviews() {
        super.layoutSubviews()
        print("CZMainTabBar: layoutSubviews")
        //计算 item的宽度
        let width = frame.width / CGFloat(TabBarItemCount)
        //计算最左边的这个frame，后面使用CGRectOffset
        let originFrame = CGRect(x: 0, y: 0, width: width, height: frame.height)
        var index = 0
        for view in subviews {
            //判断是否是UITabBarButton
            let cls = NSClassFromString("UITabBarButton")
            if view.isKindOfClass(cls!) {
                //设置每个UITabBarButton的位置
//                view.frame = CGRect(x: CGFloat(index) * width, y: 0, width: width, height: frame.height)
                
                // rect: 原始的frame
                // dx: x方向的偏移量
                // dy: y方向的偏移量
                view.frame = CGRectOffset(originFrame, CGFloat(index) * width, 0)
                index += index == 1 ? 2 : 1
//                index++
//                if index == 2 {
//                    index++
//                }

            }
         
        }
        //设置加好按钮的frame
        composeButton.frame = CGRect(x: 2 * width, y: 0, width: width, height: frame.height)
    
    }
  
    //MARK -懒加载
    //加号按钮
    private lazy var composeButton: UIButton = {
        let button = UIButton()
        //设置加号按钮的图片和背景图片
        button.setBackgroundImage(UIImage(named: "tabbar_compose_button"), forState: UIControlState.Normal)
        button.setBackgroundImage(UIImage(named: "tabbar_compose_button_highlighted"), forState: UIControlState.Highlighted)
       button.setImage(UIImage(named: "tabbar_compose_icon_add"), forState: UIControlState.Normal)
        button.setImage(UIImage(named: "tabbar_compose_icon_add_highlighted"), forState: UIControlState.Highlighted)
        //添加到tabBar上面
        self.addSubview(button)
        return button
    }()

}
